/*
 * Copyright 2017, Haiku, Inc. All Rights Reserved.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *              Akshay Agarwal <agarwal.akshay.akshay8@gmail.com>
 */


#include <unicode/uversion.h>
#include <RelativeDateTimeFormat.h>

#include <stdlib.h>
#include <time.h>

#include <unicode/gregocal.h>
#include <unicode/reldatefmt.h>
#include <unicode/utypes.h>

#include <ICUWrapper.h>

#include <Language.h>
#include <Locale.h>
#include <LocaleRoster.h>
#include <TimeUnitFormat.h>


U_NAMESPACE_USE


static const URelativeDateTimeUnit kTimeUnitToRelativeDateTime[] = {
        UDAT_REL_UNIT_YEAR,
        UDAT_REL_UNIT_MONTH,
        UDAT_REL_UNIT_WEEK,
        UDAT_REL_UNIT_DAY,
        UDAT_REL_UNIT_HOUR,
        UDAT_REL_UNIT_MINUTE,
        UDAT_REL_UNIT_SECOND,
};


static const UCalendarDateFields kTimeUnitToICUDateField[] = {
        UCAL_YEAR,
        UCAL_MONTH,
        UCAL_WEEK_OF_MONTH,
        UCAL_DAY_OF_WEEK,
        UCAL_HOUR_OF_DAY,
        UCAL_MINUTE,
        UCAL_SECOND,
};


BRelativeDateTimeFormat::BRelativeDateTimeFormat()
        : Inherited()
{
        Locale icuLocale(fLanguage.Code());
        UErrorCode icuStatus = U_ZERO_ERROR;

        fFormatter = new RelativeDateTimeFormatter(icuLocale, icuStatus);
        if (fFormatter == NULL) {
                fInitStatus = B_NO_MEMORY;
                return;
        }

        fCalendar = new GregorianCalendar(icuStatus);
        if (fCalendar == NULL) {
                fInitStatus = B_NO_MEMORY;
                return;
        }

        if (!U_SUCCESS(icuStatus))
                fInitStatus = B_ERROR;
}


BRelativeDateTimeFormat::BRelativeDateTimeFormat(const BLanguage& language,
        const BFormattingConventions& conventions)
        : Inherited(language, conventions)
{
        Locale icuLocale(fLanguage.Code());
        UErrorCode icuStatus = U_ZERO_ERROR;

        fFormatter = new RelativeDateTimeFormatter(icuLocale, icuStatus);
        if (fFormatter == NULL) {
                fInitStatus = B_NO_MEMORY;
                return;
        }

        fCalendar = new GregorianCalendar(icuStatus);
        if (fCalendar == NULL) {
                fInitStatus = B_NO_MEMORY;
                return;
        }

        if (!U_SUCCESS(icuStatus))
                fInitStatus = B_ERROR;
}


BRelativeDateTimeFormat::BRelativeDateTimeFormat(const BRelativeDateTimeFormat& other)
        : Inherited(other),
        fFormatter(other.fFormatter != NULL
                ? new RelativeDateTimeFormatter(*other.fFormatter) : NULL),
        fCalendar(other.fCalendar != NULL
                ? new GregorianCalendar(*other.fCalendar) : NULL)
{
        if ((fFormatter == NULL && other.fFormatter != NULL)
                || (fCalendar == NULL && other.fCalendar != NULL))
                fInitStatus = B_NO_MEMORY;
}


BRelativeDateTimeFormat::~BRelativeDateTimeFormat()
{
        delete fFormatter;
        delete fCalendar;
}


status_t
BRelativeDateTimeFormat::Format(BString& string,
        const time_t timeValue) const
{
        if (fFormatter == NULL)
                return B_NO_INIT;

        time_t currentTime = time(NULL);

        UErrorCode icuStatus = U_ZERO_ERROR;
        fCalendar->setTime((UDate)currentTime * 1000, icuStatus);
        if (!U_SUCCESS(icuStatus))
                return B_ERROR;

        UDate UTimeValue = (UDate)timeValue * 1000;

        int delta = 0;
        int offset = 1;
        URelativeDateTimeUnit unit = UDAT_REL_UNIT_SECOND;

        for (int timeUnit = 0; timeUnit <= B_TIME_UNIT_LAST; ++timeUnit) {
                delta = fCalendar->fieldDifference(UTimeValue,
                        kTimeUnitToICUDateField[timeUnit], icuStatus);

                if (!U_SUCCESS(icuStatus))
                        return B_ERROR;

                if (abs(delta) >= offset) {
                        unit = kTimeUnitToRelativeDateTime[timeUnit];
                        break;
                }
        }

        UnicodeString unicodeResult;

        // Note: icu::RelativeDateTimeFormatter::formatNumeric() is a part of ICU Draft API
        // and may be changed in the future versions and was introduced in ICU 57.
        fFormatter->formatNumeric(delta, unit, unicodeResult, icuStatus);

        if (!U_SUCCESS(icuStatus))
                return B_ERROR;

        BStringByteSink byteSink(&string);
        unicodeResult.toUTF8(byteSink);

        return B_OK;
}